Power
by Undersnail
Summary: You thought that Frisk was the kind, loving, loyal sunshine boy that everyone knows and loves, but what will happen when he realises that he has more power than he knew he had? Well... they do say power tends to corrupt. Rating: T - dark themes. All characters except the oracle belong to TobyFox. The oracle belongs to me.
1. Prologue

**Hello fellow UNDERTALE fanfic readers. I thought that I'd try my hand at writing a fanfic.**

 **Here's the prologue.**

 **Please note, Frisk is male in this AU**

 **Enjoy!**

* * *

 **ASGORE'S THRONEROOM-**

 **TEN YEARS BEFORE CHARA FALLS-**

Asgore was tending to his buttercups as usual… when a familiar fishy scent hit him.

"Yes Undyne?" wondering how the Monster King knew she was there, she stepped forward.

"There's someone to see you your Highness." The King did his trademark slow… very slow turn. "She calls herself the Oracle."

"Please ask her to identify her reasons for coming here… then… bring her in." Undyne flashed a quick salute and turned around walking in her regal manner… she was the head royal of the royal guard afterall. "Tori! I think you should come in dear." His (then) wife Toriel Dreamurr walked in her trademark regal, gentle fashion.

"Yes, darling?" The queen said gently.

"Just sit down for now… Undyne will explain when she- "

"Your Majesties. The lady who calls herself the oracle." Undyne announced, bowing in the presence of monster royalty. "She says that she has precognition that she absolutely must share with you."

"Welcome Ms Oracle. It is a pleasure to meet you." The small bony woman said or did nothing but nod. Suddenly, without warning she fell on the floor, face first. "Ms Oracle? Are you alright?" said Asgore standing up in astonishment. Gradually a low buzz filled the room and the Oracle's body slowly rose in to the air and righted itself. Her eyes and mouth opened as a blue light shone out of the holes that were her eyesockets and mouth.

" **THe cHIld sEvEnTh.** " Boomed a demonic voice lower than Asgore's. " **MonSter'S SaViOuR. ThE destRucTIoN of tHe bARRIeR liEs in theIR wAKe. buT WhEn tHE TrUe PoWeR to sAVe IS DIscoVeReD by tHem, thE fATe OF THe WorLd Is aT StAKe.** " The buzzing disappeared and so did the blue light. The oracle's body fell to the ground lifeless.

"UNDYNE! GET A DOCTOR!" Asgore called.

"Yes your majesty." Said the head of the royal guard running out of the room.

 **BUT IT WAS TOO LATE. FOR SEVEN YEARS ASGORE SEARCHED FOR THE CHILD OF THE PROPHECY, AND SLOWLY BUT SURELY THE PROPHECY'S EXISTENCE WAS FORGOTTEN. THREE YEARS LATER, CHARA FELL INTO THE UNDERGROUND.**

* * *

 **FRISK'S APARTMENT, EBOTTVILLE-**

 **FRISK'S SIXTEENTH BIRTHDAY-**

 _"Happy Birthday to You, Happy Birthday to You, Happy Birthday Dear Fri-isk, Happy Birthday to You!"_

"Hip-hip!" Mettaton shouted in his showman-like manner.

"Hooray!' everyone responded. This was repeated another two times, the 'Hooray' getting louder each time.

It had been four years since frisk had cleared the barrier, and three years since the move from the underground was completed. Since then, the tiny village of Ebottville had flourished into a pleasant city. Frisk lived on the fourteenth floor of Ebottville's central highrise apartment building with his boyfriend **(yes Frasriel is happening)** Asriel, and his skeleton buddies Sans and Papyrus. Frisk and Asriel had a steady two-year long relationship going. They both loved eachother to bits, and everyone knew about it due to Asriel's mother, Toriel's frequent social media posts about their romance.

"But you gotta admit, they are cute as heck together." Said Sans to his brother Papyrus.

"We can hear you!" came the muffled cry through the wall they shared with Asriel and Frisk's room which was filled with wrapping paper as the two boys were opening all of Frisk's presents.

"Hey Frisk!" Sans called.

"Hmm."

"I'm pretty sure you've noticed by now that I didn't give you a present."

"Uh-huh."

"I've got one, just I can't give it to you… I have to show it to you."

"Sure." Frisk said sarcastically.

"Meet me at the Librarby at eight."

There was no response.

* * *

 **EBOTTVILLE LIBRARBY-**

 **8PM THAT EVENING-**

"Hey Sans!" Frisk whispered.

"Hey Bud'! I didn't think you would come.

"No way I'd miss your present Sans."

"No way I'd forget a present for you kiddo." Sans grinned a bony grin.

The skeleton lead the now sixteen year old to the back of the libraby.

"Where are we going?" Frisk asked.

"You're sixteen now, right kiddo?" Frisk nodded. "I think it's time I showed you the prophecy."

* * *

 **PROLOGUE: END**

Note: if you aren't prepared to see Frisk go from our kind caring Sunshine Boy, to well… Chara, DON'T READ THIS FANFIC!


	2. Prophecy

**Hello. Welcome to Chapter One!**

 **Enjoy.**

* * *

 **EBOTTVILE LIBRARBY-**

 **WHERE WE LEFT OFF-**

Sans and Frisk walked towards the back of the Librarby. There they stood. In front of a wall.

"What the hell." Frisk said dryly.

"Oho! Just you wait Bud'." Sans swiped his hand on the wall. It rippled and revealed a keyboard. He typed something too quick to see. Then suddenly the wall slid downwards revealing an old looking stone passage with lamps leading down a stairwell. The pair slowly tiptoed down the passageway. "Here we are." The two stood in front of what seemed to be an ordinary bookcase, but considering that Sans just made a wall reveal a passageway, Frisk doubted that the bookcase was normal. Each book had a fifteen-centimetre-wide spine and was about 25 centimetres tall. The spines were all silver and had golden numbers on them from one to a hundred.

"This is the entire history of the Underground!" Sans announced proudly. For once he didn't seem like he wanted to be asleep.

"Woah!" Frisk responded. "No… That can't be all."

"Heh heh.." you're right about that. Sans put his hand on the top row of books and slid it to the left. All the rows started to move left. When a book reached the end of a row it reappeared at the opposite side of the one above it. Books in the top row completely disappeared, and completely new books appeared at the right side of the bottom row. By the end of the process, the bookcase was filled with a completely new set of books numbered 101 to 200. Frisks jaw dropped. He'd seen the God of Hyperdeath and this was still more amazing to him.

"These books record every single thing that occurs in the Undergound." Sans started. "Every little meeting between monsters, every bit of research, every human… Everything." Sans scrolled until he could see the book he was looking for. "Ahh. Number 723, the most important of the lot in my opinion." Suddenly, he frowned. "You're not gonna like what I'm about to show you." Sans opened the book, and flicked through the pages for a while until he found one he seemed to like. "I'm sorry Frisk, but I don't think you'll like your present." Sans handed him the book and pointed to a paragraph.

 _The Oracle uttered these words:_

 _The child seventh_

 _Monster's saviour_

 _The destruction of the barrier_

 _Lies in their wake;_

 _But when the true power_

 _To save has been discovered by them_

 _The fate of the world_

 _Is at stake._

Frisk looked up with his trademark blank expression on his face.

"So… Whats on your mind Kid?" Sans questioned.

"Why? Why did you show me this?" Frisk wasn't going to react well to anything but an answer.

"Well… You had to be told… and you're sixteen now… so… I thought it was about time for you to find out."

"I know I'm the child in the prophecy, Sans, but what does it mean? What does it mean by the fate of the world is at stake?"

"That's for you to decide…"

"Sans!"

"Sorry I couldn't resist… but it really is for you to decide." Frisk scowled at this. "I mean you have a choice." Frisk's look changed from a scowl to a serious but intrigued gaze. "The way I interpreted it is that… you could either use the power you receive to help people… or… you could… and I really hope this never happens… the power… I guess… could corrupt you… and you could… um I really don't know how to put this… but, I guess, you'd turn really destructive and kill anyone in your path because they oppose your view…" Tears welled up in Sans' eye sockets as he trailed of at the end of his spiel. "I'm sorry Frisk. I didn't want it to be this way on your birthday, but- "

"I understand Sans." Frisk interrupted looking down. "I just hope the prophecy doesn't come true either way… I…I…I just don't think that I'm ready for the responsibility." His hair covered his eyes as tears streamed down his face. "I'm just so afraid that I'll go down the bad path because of that…" Frisk shoved his face into Sans' jacket like he'd done so many times before… "I'm such a goddamn crybaby, Sans, but I just can't help it" he explained between sobs. Sans grabbed Frisk's shoulders and stood him upright.

"Look at me Frisk." One friend looked at the other. "I don't care whether you _think_ you're ready to accept this responsibility or not, because I know for sure that you are. I know that you will make the decision that you think is right, and I know for sure that the decision you make will benefit us all."

"Thanks, Sans… but its gonna take a while to get confident about what to do when it happens." Sans nodded his head.

"Come 'ere Kiddo." Frisk ran in for another hug, but this time there were no tears. Just happiness. Happiness because there was someone to support him. "You know bucko, it still feels like yesterday, that you saved Asriel and broke the barrier. Now… you're sixteen… you've grown taller, stronger, smarter. Your voice ain't as high pitched, you've got a boyfriend." Frisk's face went deep red. "Kid, there's only one way to explain it. You're growing up, Frisk."

"You know Sans, it's weird," Frisk started, pulling away from the hug, "You're acting like my Dad did before he passed." Sans' face went light blue as he blushed. "And I don't like it." Sans suddenly looked quite scared that he'd hurt his friend. "Because the way you normally act… is like a dad to me anyway and… I guess I just like you better that way. Sans' face went a deep shade of blue.

"Sans, could I call Azzy down here… I think he should know…"

"Good idea." Frisk took out his phone and dialled his boyfriend.

"Hey Az."

"Hey Gorgeous."

"Your voice needs to be deeper than your dad's to pull that off." …Silence…

"Well I was just about to call you. You've been at the Librarby for, like, two hours or something now, what's going on?"

"Yeah sorry about that Az… Actually, I was wondering if you could come down here so we can explain."

"Sure thing. I'll be there in ten."

"See ya Az!"

"See ya babe!"

"Stick to Frisk until you sound manly." Frisk said as he hung up. "He'll be here in ten minutes, Sans."

"Ten minutes is enough time to grab a snack… Grilby's?"

"Sure."

"Follow me. I know a shortcut."

* * *

 **CHAPTER 1: END**

 **Nice spot to end I think. See you next chapter.**


	3. Power

**Welcome to Chapter 2.**

 **Enjoy!**

* * *

 **EBOTTVILLE LIBRARBY-**

 **AFTER ASRIEL GETS AN EXPLANATION-**

"Wait, so you're telling me that Frisk has a whole heap of abilities that he doesn't know about, and when he finds out how to use them, he'll either make the world the most amazing place or destroy it?" Asriel questioned. The human and skeleton nodded. "Frisk… I don't know what to say… I'm just so… happy for you, and the world, 'cause… I know for sure that you'll make the world a great place."

"Thanks Az." Frisk replied, grinning at his boyfriend's reaction.

* * *

 **CENTRAL EBOTTVILLE PATH-**

 **TEN MINUTES LATER-**

Frisk was happy. No, more than that. Frisk was ecstatic. He had someone to support him. No, not just one person but two people to support him. Slowly he was gaining confidence that he would make the right decision…

'Now would be a good time to save…" Frisk thought. "If there was a save point."

Right then, without warning, Frisk's vision blacked out. He opened his eyes but all around him was darkness. Never-ending darkness. However, the room, or whatever the space was called, gradually began to fill with light. Words in the white font he'd seen so many times before appeared. They read: _Would you like to SAVE?_ Underneath, the options 'yes' and 'no' awaited Frisk's response. Frisk slowly inched towards the yes option.

'Is this the power that the prophecy told of? Saving at any time?' Frisk wondered, the yes option only about twenty centimetres away from him now. Frisk slowly raised his hand and touched the word as it turned yellow. Frisk curled his hand into a fist and when he did, the room was flooded with light. A new set of words appeared in place of the last. _Saved. Would you like to make changes to the save file?_

'What?' Frisk's thoughts ran wild. 'Changes? I can alter reality? What? That can't be!' Thinking that he shouldn't mess with time, he walked towards the 'no' option that had now appeared along with its 'yes' counterpart… but curiosity was irking him. He wanted to know what he could do. He was reminded of the torture he put Sans through by the number of times he reset. A pang of guilt shot through him. Curiosity. Curiosity is something to have in moderation. Still, after thinking this he changed course towards the yes option. Curiosity had struck again.

'Why am I doing this.' He thought, and Once again, the room was engulfed in light. Frisk stood in a room. A blue room. With a door on each of its four walls. Each door had a label. One read 'people'. The others read: 'places', 'objects' and 'actions'. There was also a trapdoor on the floor which Frisk assumed was for when he was done with whatever was past the doors.

"'People' sounds good" Frisk said to himself as he walked through the respective door. A bluish light filled the room. Frisk marvelled in awe. The vastness of the room felt infinite. In front of him was a holographic image of every single person he had ever met, read, or heard about. Directly In front of him was Papyrus. He walked forward and touched his friends image. Immediately all the other images disappeared. Frisk stared at what seemed to be a data card about Papyrus. His height, weight, and a description of him lay before Frisk. He read the description.

 _Papyrus the Skeleton is the brother of Sans the Skeleton. Though Papyrus is almost a skull taller than his brother, he's a bit thick and lacks common sense._

The description went on to describe his role in the underground in each possible timeline which took up about ten square metres of space. Frisk then noticed three buttons labelled 'edit', 'remove' and 'back' which he assumed would take him back to the holographic images of everyone. Curiosity struck again. First there were timelines. But now there was an infinite number of possibilities of what he could do.

Frisk tapped edit and changed Papyrus' height from 1.87 metres to a measly 1.5.

"Heh." he laughed. "If it's too bad I'll change it back." Frisk went back through the door and explored, and he found that he could do the same thing to buildings and structures, objects, and the actions that people performed. Excited he opened the trap door and hopped in. There he was back on the path in front of his apartment building. He checked the time. 11:47pm exactly when he'd saved…

"I guess time stops when I do that…" Frisk said under his breath. "I better go tell Az"

* * *

 **FRISK'S APARTMENT-**

 **11:55PM-**

The door was opened by Asriel.

"Hey Frisk!" Asriel called.

"Hey Azzy!" Frisk replied.

"Sans and Papyrus are watching TV, c'mon."

"Actually Az, I was wondering if- HOLY CRAP IT WORKED!" a 1.5-metre-tall Papyrus was leaning on the sofa. "AND HOLY CRAP IT'S SCARY!"

'Let me save please…" Frisk thought. Immediately, he was transported to the black room. He changed Papyrus' height back as quickly as he could and hopped down the trap door sighing a sigh of relief after seeing that Papyrus was taller than him.

"What worked and why is it scary!?" Asriel exclaimed, clearly confused.

"Sans, Az could we talk for a minute?" Frisk asked. Sans stood up as Asriel nodded his head.

"WHAT ABOUT ME!" Papyrus whinged.

"Shut up Pap." Sans retorted.

"HHMMMPPHHHH!" Papyrus sulked. "OOHH LOOK! METTATON'S SHOW IS ON!" Papyrus exclaimed gluing his eye sockets to the television.

The remaining three not crazy people in the apartment went into Frisk and Asriel's room.

"So. What's up?" Asriel asked quizzaciously.

"It happened."

* * *

 **CHAPTER 2: END**

 **A bit short, but I thought this would be a good place to end the chapter.**


End file.
